You may have already heard about your car's Green NCAP rating: but how exactly does this rating system work? Let's find out in this Karfu article.


What is the Green NCAP rating?


With carmakers continuing to face ever-more-stringent emissions regulations, more and more drivers have become interested in the world's fate, starting with the waste produced by their cars, parameterised by their carbon footprint. That's where the Green NCAP rating comes in: a metric created to promote awareness, with the aim to develop clean, energy-efficient vehicles that produce no harm to the environment.


Similar to the Euro NCAP safety rating, the Green NCAP rating utilizes a star system that raises awareness of the possible harmful implications of the car to the environment. The star rating is calculated through an analysis of specific 'green' credentials - like energy emissions and waste footprint. The testing involves a meticulous investigation that is intended to give an overview of profound accuracy, embracing an idea of universality that can be applied and utilized worldwide. Trials and examinations are conducted in both a laboratory and on the road, with specific vehicles not directly sourced from the manufacturer, to ensure that the car examined hasn't been tampered with.


What happens in the laboratory?

When put into examination by engineers in a lab, the car is placed on a chassis dynamometer (also called a 'rolling road'). This is an experiment in which the car is driven through a series of possible realities on the road. It goes through a series of tests to ascertain the different types of performance attributable to the vehicle. The analysis aims to ascertain the amount and type of emissions produced by the exhaust and the amounts emitted during the run through different 'real-life' scenarios and various altering resistances.


The laboratory tests are inspired by the standardized World-Harmonized Light-Vehicles Test Cycle (WLTC) testing, introduced in 2017. Yet, the quality of NCAP's tests is further reinforced by a cross-reference in both the accuracy and definition of the results. Using a less regularised and more reality-oriented interpretation of the data - taking its lead directly through road tests (through careful handling of car temperatures on the road, for example) - it settles upon a more realistic view of the results.


What happens on the road?


After the laboratory tests, NCAP concentrates on the direct analysis of the road in the day-to-day world. Through portable equipment directly installed onto the vehicle during a trial, this process can now record the amount of waste produced by the exhaust gasses and then analyze it in the secondary stage. Again, the tests are based on past RDE standards (dating back to 2017). But NCAP has noted a change in the analysis, introducing different factors drawn from everyday life (such as variable traffic factors).


The analysis is based on driving through three travel stages: urban, rural and motorway. During the test, the vehicle goes through temperature changes, passing through different stages - starting with a cold start and then moving up to the nominal operating temperature. Driving is carried out in different styles so that the various locations of operation can be verified during sudden acceleration and braking, slowing down and a change in driving performance. 


Once the analysis is complete, the results are translated into language based on a strictly NCAP-marked star system, which allows the identification and accurate determination of what characterizes the vehicle in a dynamic focused on the protection of the environment as a whole.


The results are divided into three main categories for objective evaluation: the Clean Air Index, Energy Efficiency Index and Greenhouse Gas Index. They are interconnected: a negative review in any category will likely affect and reduce the average score and final results. 


Green NCAP Ratings: how does it work?

Five stars: Overall excellent performance, showing very low fuel or energy consumption and at the same time emitting common pollutants and greenhouse gasses. Well equipped with emission reduction and fuel-saving technology.


Four stars: Overall good environmental performance; equipped with excellent and robust emission abatement and fuel-saving technology.


Three stars: Average to good overall performance but equipped with regular emission abatement and fuel-saving technology fitted, not outperforming competitors.


Two stars: Nominal overall environmental performance lacking some emission reduction and fuel-saving technology with room for improvement.


One star: Marginal environmental performance showing that pollutant control and energy efficiency are compromised. the outcomes indicate that the ecological impact of minimizing the production of waste, greenhouse gasses and energy consumption requires an overhaul to redesign the system used by the vehicle 


Zero stars: Performance meets minimum standards, using an obsolete system that will soon be taken off the market


From 2020, half stars have been introduced in the NCAP system: these represent a kind of bonus, awarded as a ‘reward’ to vehicles that strive to improve their performance, behaving better in the dynamics of a competitive market.

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Silvia Iacovcich 27/04/22